Top-sealing process



A. J. wElss TOP SEALING PROCESS Filed Aug. 4, 1927 April 29, 1930.

Patented Apr. 29, 1930 UNITED s'rArss encreurv orrisff ARTHUR J. VITEISS, OF WEST ORANGE, NEW JERSEY, ASSIGNOR TO DUBILIER CON- DENSER CORPORATION, OF NEW '-YORK, N. Y., A CORPORATION OF DELAWARE TOP-SEALNG- PROCESS Application i'iled August e, 1927. Serial No. 210,560.

This invention relates to improvements in electrical condensers; particularly electrical condensers that are impregnated with a filler of insulating material in the course of their manufacture and that are then closed by A means of a layer of hard wax forming a seal.

An object ofthe invention is to provide a layer of heat insulating compound that will prevent the melting of the filler from the heat of the layer of molten sealing compound at the time of its application.

A further object is`to provide a material which has important advantages over the materials heretofore lin use as heat insulators or barriers, and which improved Vmaterial will form a substantial bond between the cell j and the filler.

These and other objects and advantages of the invention will be clear from the following description, taken with the drawings, which show how the inventionis practiced. The disclosure, however, is illustrative only, and I may change the details of what is actus ally shown, particularly as to shape, size and arrangement of parts, without exceeding the scope of the appended claims.

On the drawings- Fig. 1 isa longitudinal section through a condenser, according to my invention; and

Fig. 2 is a top plan thereof, partly broken away.

The numeral 1 indicates the body of a condenser which may comprise one or more seotions. This body may include sheets or strips of some electrical'conductive substance such as metal foil separated by insulation such as paper, and after the body is formed it may be impregnated by immersing in melted wax', and alternately subjected to evacuation and pressure. It is then placed in a container 2 which may be of sheet metal, cardboard, or other material, and into vthis container is poured a liquid insulating compound such as wax, indicated at 3. @ne end of the casing may be open, and through this end may project the terminals i of the body of the condenser 1. This open end of the condenser may be closed with suitable material such as wax 5 to seal the body of the condenser in Y the casing 1 and cover both the body and the wax 3 and the edges of the open end of the container 2 may be crimped over upon the scaling material 5, as indicated at 6.

ln the manufacture of paper condensers it has heretofore been usual to put betweenthe wax or other insulating substance or filler 8 and the sealingcompound 5 a barrier of some sort, such as a sheet of fibre or cardboard, or some other insulating material. The presence of such a barrier has given rise to some trouble by preventing a good joint between the wax 3 and 5, and 1t entails some extra eX- 4pense in the way of itting into place and properly mountinfr it'adjacent the ends of the condenser 1. llt has been found that the disadvantage incident to the use of a sheet of libre between the filler 3 and sealing oom pound 5 can be eliminated by the use of a layer of sharp silica or sand of high insulating qualities. However, the use of sand and of other light material, such as talc, as a heat insulator between the low meltingpoint filler which may be paraffin and the high melting point top seal has been found somewhat objectionable for several reasons.

One such reason is that neither sand nor talc provide a means for bonding a top 'seal to the paralin filling, or between the top seal and the tops of the section units or units that go to make up the condenser. The top seal therefore is fastened only by its edges Where it is in Contact with the can or other container. Under these conditions, in a condenser provded with a sand or talc barrier and placed on its side andl subjected to a moderate temperature (of the order of 125) for a period of two or three hours, the unsupported top seal will bulge and slough away.

Another reason that renders the use of sand objectionable, is the tendency of the sand to get between and puncture the paper dielectric or other materials that go to make up the units out of which the complete condenser is assembled.` Its presence during salvage operations is particularly undesirable as itis almost impossible to get rid of it. Where sand has been used as a barrier, salvaged sections are of very doubtful. valuei Efforts to overcomethe aforementioned diculties and at the same time' retain the numerous advantages which are lnherent 1n the use of sand and talc, has lead to the use of a powdered hard wax or seal 7, or any powdered or granulated substance having the requisite characteristics, the principal requisite being that this powdered hard Wax should have a melting point intermediate that of the high melting point of the seal 5 and the low melting point of the filler Wax 3.

Upon application of the hot top seal 5 the granular barrier material 7 will melt or become plastic and fuse sufficiently to act as a bond between the top seal and the `paraffin filling. Upon cooling, a Solid, stratiiied, void-free formation will result, wherein there are very few free particles and every layer is thoroughly bonded to the one adjacent thereto over the entire area of the top of the condenser. 'All wires to the terminals will be rigidly held in place and short circuits due to shifting terminals, blocksand Wires which Vas - mediate that are free to move in sand or talc will be rigidly held in place.

Having described myinvention, what I be-v lieve to be new and vdesire to secure and protect by Letters Patent of the United States 1s:

1. -A condenser comprising 'a body, a container therefor, a iiller of easily fusible material, a less readily fusible compound for sealing the container, and a layer of heat insulat` ing material having a melting point interof said filler and that of thel compound for sealing the container.

2: A condenser comprising a body, a container, a filler of low melting point for the body in the container, the container being open at one end, a sealing compound in said end, and a layer of Wax betwee the sealing compound and said filler. t

3. In a condenser an impregnated body, a fusible seal, and a substance between the seal and body which is rendered plastic by the seal when' applied and-then hardens to secure the seal to the body.

l In testimony whereof I aix my signature.

ARTHUR J. WEISS. 

